R: generate dataframe of Friday dates for the year [duplicate]

Answer 1

I think this would be the most efficient way and would also returns all the Friday in the whole of 2013.

FirstWeek <-   seq(as.Date("2013/1/1"), as.Date("2013/1/7"), "days")
seq(
  FirstWeek[weekdays(FirstWeek) == "Friday"],
  as.Date("2013/12/31"),
  by = "week"
)